Fluorescence cytometry has developed over the last decade into a powerful methodology that has found numerous applications in cell biology ranging from morphological characterization of cellular structures to determination of kinetics of chemical reactions within a single cell. Three major factors made equally important contributions to this progress; development of a wide variety of fluorescent probes, many of which are quite specific and can be used in the living cell; improvement of instrumentation in which the use of laser gave a significant boost; and, advancement of software through which a digital image processing and quantitative analysis was introduced. Although further developments in these areas are both welcome and inevitable, the state of the art is sophisticated enough to call for new experimental designs which should elucidate physiological and pathological processes at subcellular levels. The purpose of this proposal is to secure funds and purchase an adequate instrument which would enable a group of investigators to apply digital imaging fluorescence microscopy in their respective projects. These projects include studies of the role of lipoprotein subspecies in atherogenesis and reverse cholesterol transport; structural alterations of apolipoprotein B and cholesterol deposition in cells; cellular lipid changes modulated by apolipoprotein C-III; regulation of lipoprotein synthesis, production of B lymphocytes within hemopoietic tissues; autoantibody generation in rheumatic diseases; and the role of membrane fluidity in cellular activation. The proposed instrument, "ACAS-470" Workstation for Anchored Cell Analysis and Sorting, represents an integration of microscope, laser, micropositioning and computer technologies. ACAS-470 allows quantitative fluorescence image analysis, analysis of fluorescence redistribution after photobleaching (FRAP) as well as automated selection of anchorage dependent cells in culture. This combination of performances is well-suited to the variety of experimental approaches designed within included projects. ACAS-470 is currently the only instrument on the market that allows fluorescence analysis, fluorescence redistribution after photobleaching (FRAP) and cell sorting of anchorage dependent cells.